Radio antenna



P 5, 1939- J. M. BEAUFORT El AL 2,172,117

RADIO ANTENNA Filed May 2, 1938 Jahr/V. a a/b/z flax/4172 6 P a/' ATTORNEYS Patented Sept. 5, 1939 PATENT OFFICE RADIO ANTENNA John M. Beaufort and Howard 8. Pyle,

Seattle. Wash.

Application May 2, 1938, Serial No. 205,605

2 Claims.

This invention relates to radio antennas, particularly to antennas of the mast type for use with radio apparatus installed on motor cars.

It is common practice in radio-equipped motor cars, such as police prowl cars, to mount a transmitting antenna at the rear of the car, or in some instances, on the running board or side of the body. Such antennas generally consistot a flexible metallic rod, arranged in two or three telescopic sections, so that it may be carried in a telescoped position or extended to any predetermined height by manually pulling the inner sections from the lower sections. It is accordingly exceedingly inconvenient to carry such an antenna in a normally telescoped position, and to manually extend it to the necessary height required each time the radio equipment is to be used. To do so means that the motor car must be stopped, the operator must leave his seat, ex-' tend the antenna and return to the radio operat ing position, reversing the process when the communication is finished. 'By reason of this inconvenience, it has become common practice for operators of such radio equipped motor vehicles to operate the motor car in transit with the antenna extended to the required height for normal radio-operation, thereby constituting a hazard in that the average antenna is approximately eight feet long, and vertically mounted, causing it to extend to a point several feet above the root level of the car. The antenna is accordingly endangered during travel of the vehicle, by overhanging limbs, low doorways and underpasses, and similar objects. Dependence is placed on the flexibility of the antenna mast for protection in such cases, it being expected that it will bend or give sufiiciently to clear such objects, retuming to an upright position by reason of its construction of a springy material. In actual practice, such an antenna is unsatisfactory.

With the above disadvantages in mind the present invention has for an object to provide an antenna formed of telescopically assembled sections which may be carried in normal transit in a telescoped position of such length that it offers no hazard such as accidental contact with fixed objects, and which may be instantly extended into any predetermined length by a fluid pressure medium controlled from the instrument panel of the vehicle.

A further object is to provide an antenna of this type which will be formed of a few strong simple and durable parts, which will be inexpensive to manufacture and install and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be re sorted to within the scope of the appended claims without departing from the spirit or sacrificing any of the advantage of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a side elevation of an antenna constructed in accordance with the invention, in extended position, and provided with a rear bumper mounting bracket.

, Figure 2 is an enlarged longitudinal sectional view of the antenna in telescoped position.

Referring now to the drawing in which like characters of reference designate similar parts in the various views, It designates the lower or main body of the mast antenna, the same preferably belng formed of a metal tube or pipe which is provided at the bottom with a pipe flange I I which in turn is secured to the top of a conventional insulator l2 through the medium of cap screws l3. An angular rear bumper mounting bracket M is secured to the bottom of the insulator and is provided with a U-bolt I5 for securing the antenna to the rear bumper of a motor vehicle.

The lower end of the body is formed airtight at its point of mounting on the insulator and forms an air chamber into which compressed air or gases are introduced through a suitable pipe nipple it which is threadedly engaged in an opening H in the side of the body directly above the pipe flange H. Preferably the fluid pressure medium is conducted to the nipple from its source of supply by a suitable pipe connection l8 which is controlled by a suitable valve mechanism on the instrument board of the vehicle within convenient reach of the operator.

The top of the antenna body In is provided with a cap I 9 which serves the dual purpose of forming a closure for the body and providing a guide for centering the intermediate section 20 of the antenna. The cap is provided with an opening 2| through which the intermediate section may freely move. 7

Disposed on top oi the cap is a soft rubber gasket 22 which serves as a bumper for the intermediate section when the latter is lowered, thereby preventing an abrupt metal to metal shock for a metal stop sleeve 23 which surrounds the lower end of the intermediate section and engages the inner face of the cap I! to limit extending movement of the intermediate section relative to the body ID. The sleeve is held in place through engaged with the inner surface of the intermediate section. The bushing is provided with a collar 25 upon which the stop sleeve is supported.

- tered and return to initial positionafter the ob- A second bushing 28 is threadedly engaged with the inner surface of the bushing 24 and is provided with-a central opening 21 .of suflicient diameter to permit passage of compressed air or gas from the body into the intermediate sec tion in order to lift the tip section to extended position.

The bushing 26 is provided with a collar 23 which clamps a leather cup piston against the collar 25 of the outer bushing 24. when air or gas is applied to the bottom surfaceof the cup piston the piston expands against the inner wall of the body ill and formsan air seal which prevents the air or gas escaping past the piston so that pressure of .the gas below the piston forces the intermediate section 20 to extended position. A vent opening 30 is formed in the body l0 near the cap I! to vent the interior of the body above the piston so that movement of the piston under urge of incoming compressed air or gas, will not be impeded by the piston compressing air ahead of it against the cap [3.

Acap 3| is threadedly engaged with the top of the intermediate section 20 and is provided with a central guide opening 32 to receivethe upper section 33 of the antenna mast. -The upper sec- .tion preferably is formed of a solid resilient rod adapted to yield when an obstruction is'encounstruction is passed. A ball 34 is threaded on to the top of the rod section to lend a finished appearance to the antenna.

A sleeve 35 is mounted on the lowerpnd of the rod section 33 and is held in place by a nut. 35 which is threaded on to the lower end of the rod section, The sleeve performs the dual function of weighting the rod section to promote quick gravitation thereof and at the same time performs the function of a stop which engages the cap 3i and limits extending movement of the rod section.

' A flexible cup piston 31 is secured to the rod section 33 through the medium of a nut 38 which clamps the piston against the sleeve securing nut 36. The piston forms a seal in the intermediate section 20 past which no compressed air or gas can escape. Pressure of air or gas against the bottom of the piston 31 forces the rod section 33 to extended position. An air vent 38 is formed in the side of the intermediate section below the cap 3! and vents the interior of the intermediate section to the atmosphere so that the piston will not compress air ahead of it against the cap 3| when moving upwardly under the urge of incoming compressed air or gas.

A soft rubber gasket 39 is disposed. on top of the cap 3| of the intermediate section and forms a bumper to receive the ball 33 without shock and also prevents access of rain and other moisture of the interior of the intermediate section 20.

In operation the mast antenna constructed as above described is ordinarily carried in the telescoped position preferably with the radio receiver connected to it in operative position to receive calls at all times. Upon receipt of a call that requires an answer, or in the event it is desired to transmit a call, the vehicle operator merely extends the antenna to the proper height by Y admitting compressed air or gas to the interior of the antenna, and at the completion of the communication the fluid pressure medium may be withdrawn from the antenna to permit the antenna to immediately gravitate to its normal telescoped position.

From the above description it is thought that the construction and operation of the invention will be fully understood without further explanation.

What is claimed is:

1. A radio antenna for motor vehicles com prising a hollow body, a rear bumper mounting bracket fixed to and insulated from the body, a tubular connection on the body for admitting a motive fluid to the body, a tubular intermediate member telescopically engaged in the upper end of the body, a piston carried by said member engaging the body and against which said motive fluid exerts'pressure to extend said member vertically from the body, a bushing in the lower end of the member having means for securing said piston in position and having an axial opening of less diameter than the diameter of the member to permit restricted escape of the motive fluid from the body into said member, a tip member the tip member piston respectively, and preventing the pistons from compressing air ahead of them when moving upwardly.

2. A radio antenna for motor vehicles comprising'a hollow body, means for mounting the body in vertical position, means for admitting a motive fluid to the body, a hollow intermediate member telescopically engaged in thebody, a piston carried by the lower end of said member, there being a restricted axial opening in the piston permitting escape of the motive fluid from the body into the intermediate member, a sleeve on the intermediate member above the piston adapted to engage the upper end of the body for limiting upward movement of the member, said sleeve also weighting the member to promote quick gravitation thereof when the motive fluid is withdrawn therefrom, a tip member telescopically engaged in the intermediate member, a piston on the tip member against which the motive fluid in the intermediate member acts to extend the tip member, a sleeve on the tip member above the piston for performing the dual function of a stop to engage the upper end of the intermediate member and limit extending movement of the tip member and also forming a weight to pro- ,mote quick gravitation of the tip member when 

